Question

我已将属性文件中的限定符名称设置为isomessage.qualifier=isoMessageMember1:

public class BankBancsConnectImpl implements BankBancsConnect{

    @Autowired
    @Resource(name="${isomessage.qualifier}")
    private Iso8583Message iso8583Message;

    public BancsConnectTransferComp getFundTransfer(IpsDcBatchDetail ipsDcBatchDetail) {
        bancsxfr = iso8583Message.getFundTransfer(bancsxfr);
    }
}

$ {isomessage.qualifier}的值是静态的，因为它在属性文件中定义。但是我希望它是动态的，并根据某些条件从数据库中获取它的价值。例如，我有多个Iso8583Message（成员明智）的实现，并且必须调用当前登录的各个成员ID类。请指导我以最好的java弹簧方式实现这一点。

我的实现类看起来像这样：

@Service("isoMessageMember1")
public class Iso8583MessageEBLImpl implements Iso8583Message{
    public BancsConnectTransferComp getFundTransfer(BancsConnectTransferComp bancsxfr) throws Exception {
    ...
    }

Answer 1

You can use Condition instead Qualifier if you are using Spring4+.

First, you need a ConfigDAO which read the qualifier name which you need from database.

public class ConfigDAO {

    public static String readFromDataSource() {
        return " ";
    }
}

Suppose there are two implemetions of Iso8583Message, you can create two Condition objects.

IsoMessageMember1_Condition

public class IsoMessageMember1_Condition implements Condition { 

    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        String qualifier = ConfigDAO.readFromDataSource();
        if (qualifier.equals("IsoMessageMember1_Condition")) {
            return true;
        } else {
            return false;
        }
    }
}

IsoMessageMember2_Condition

public class IsoMessageMember2_Condition implements Condition {

    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        String qualifier = ConfigDAO.readFromDataSource();
        if (qualifier.equals("IsoMessageMember2_Condition")) {
            return true;
        } else {
            return false;
        }
    }
}

Return different implemetion according to condition in config class.

@Configuration
public class MessageConfiguration {

    @Bean(name = "iso8583Message")
    @Conditional(IsoMessageMember1_Condition.class)
    public Iso8583Message isoMessageMember1() {
        return new Iso8583MessageEBLImpl();
    }

    @Bean(name = "iso8583Message")
    @Conditional(IsoMessageMember2_Condition.class)
    public Iso8583Message isoMessageMember2() {
        return new OtherMessageEBLImpl();
    }
}

Remove the @Qulifier and @Autowire annotations which you do not need anymore, you can retrieve the message from context every time you use it.

public class BankBancsConnectImpl implements BankBancsConnect{

    private Iso8583Message iso8583Message;

    public BancsConnectTransferComp getFundTransfer(IpsDcBatchDetail ipsDcBatchDetail) {
        iso8583Message = (Iso8583Message)context.getBean("iso8583Message");
        bancsxfr = iso8583Message.getFundTransfer(bancsxfr);
    }
}

Answer 2

在春季，可以自动连接应用程序上下文，并根据其名称检索任何bean。例如，您的界面签名类似于以下语法

 public interface Iso8583Message {
        public String getFundDetails(String uniqueId);
    }

和2种不同的实现方式遵循以下格式

@Service("iso8583-message1")
public class Iso8583MessageImpl1 implements Iso8583Message {
    @Override
    public String getFundDetails(String uniqueId) {
        return "Iso8583MessageImpl1 details ";
    }
}

和

@Service("iso8583-message2")
public class Iso8583MessageImpl2 implements Iso8583Message {
@Override
public String getFundDetails(String uniqueId) {
     return "Iso8583MessageImpl2 details ";
   }
}

我们可以按以下方式检索bean

    public class BankBancsConnectImpl implements BankBancsConnect{

           @Autowired
            private ApplicationContext applicationContext;


            public BancsConnectTransferComp getFundTransfer(IpsDcBatchDetail 
             ipsDcBatchDetail) {
            //for retrieving 1st implementation
            Iso8583Message iso8583Message=applicationContext.getBean("iso8583-message1", Iso8583Message.class);
           //For retrieving 2nd implementation
            Iso8583Message iso8583Message=applicationContext.getBean("iso8583-message2", Iso8583Message.class);
                String result = iso8583Message.getFundTransfer(bancsxfr);
            }
        }

在这种情况下，我们可以配置数据库名称而不是硬编码值（“ iso8583-message1”，“ iso8583-message2”）。

根据运行时的条件从数据库中获取@Qualifier名称

2 个答案: